(3.) It must be safe, firm and hard, with an even face and yet giving sufficient foothold to horses. (4.) It must be as noiseless as possible. (5.) It must be so constructed as to be quickly laid down and repaired when broken up for water, gas, drains, or other purposes. (6.) It must be of strong foundation, so as to carry the heaviest weight without subsidence. (7.) It must be of such a shape as will throw off all surface water at once. (8.) It must be of such materials as will make a minimum of dust or mud. (9.) It must be easily cleansed. (10.) It must be non-absorbent of impurities or moisture of any kind. (11.) It must give easy traction upon its surface. (12.) It must not cause jolting to the traffic. (13.) It must not injure horses’ legs or hoofs. Of the above requirements No. 1 affects the ratepayers alone; Nos. 3, 11, 12, 13, affect the traffic only, except that the occupiers of shops are indirectly affected by them; No. 4 affects both traffic and occupiers, and No. 10 affects the occupiers principally. The remainder of the requirements affect all three interests. With reference to the wearing effect of traffic upon the surface of the roadway, no standard has yet been arrived at by which this can be determined with accuracy. In France a great number of observations and experiments have been made from time to time by the engineers of the Ponts et Chaussées, but their practice has been to count the number of “collars” passing a given section of a roadway in a given time, irrespective of the weights, speeds, or number of wheels such collars may be drawing. Mr. Deacon, the former Borough Engineer of Liverpool, has, however, reduced traffic to a standard of tons per yard width of roadway per annum. This he effected by having the traffic in any street carefully watched for a certain definite time, the number of vehicles, their character and approximate weight being noted as well as the number of horses by which they were drawn, and their number of wheels. The effect of the traffic thus tabulated, arranged, and reduced to ton yards per annum, can be ascertained upon any roadway, and Mr. Deacon has given the results of his observations in a valuable paper on the subject of street carriage pavements which he read before the Institution of Civil Engineers.[7]